This invention relates generally to floatation sleep systems, and more particularly to a mechanism for maintaining the shape of a floatation sleep system.
Floatation sleep systems, commonly referred to as waterbeds, have become a popular alternative to conventional bedding. Such popularity is due to the fact that waterbeds provide totally balanced body support which has been found to induce a superior state of relaxation. The first waterbeds were free standing, flexible bladders filled with water. However, since the free standing bladder was flexible in all directions, it was necessary that it have a vertical dimension (height) to prevent "bottoming out" when the body was supported on the bladder. This height made it awkward to get on and off the bladder, and the fact that the side walls of the bladder were flexible made sitting on the edge difficult. Therefore, a rigid frame was added, the frame being located around the lateral marginal edges of the flexible bladder. While the frame supported the bladder to maintain a desired height and prevent bottoming out, sitting on the edge and getting in and out of the waterbed over the frame was still uncomfortable.
In order to improve the comfort of the waterbed, the frame was replaced by compressible air chambers along the lateral marginal edges of the flexible bladder, such as shown in U.S. Pat. Nos. 3,778,852 issued Dec. 18, 1973 in the name of Penn et al and 4,079,473 issued Mar. 21, 1978 in the name of Philips, for example. The air chamber provided comfort when entering and exiting the bed and when sitting on the edge thereof, and in addition maintained the fluid bladder at a desired height to prevent bottoming out. However, due to the nature of the materials forming the bladder and the air chambers, the fluid pressure within the bladder causes the mattress to bow outwardly along the longer of the opposed marginal edges. Such bowing is undesireable in that it adversely effects the overall appearance of the floatation sleep system.